Distribution of surface oxygen complexes on activated carbons from immersion calorimetry, titration and temperature-programmed desorption techniques

The chemical nature of surface oxygen complexes, their amount and the interaction with other molecules was investigated. Two oxidized activated carbons were treated in helium flow to partly remove the surface oxygen complexes. Temperature-programmed desorption (TPD) was used to study the surface oxygen complexes of these samples. The enthalpies of immersion of samples into benzene and water and the corresponding enthalpy of neutralization into sodium hydroxide were determined with a calorimeter. The neutralization enthalpy increased with temperature to show that surface area and micropore volume increase during outgassing.